The present disclosure relates generally to display systems. More particularly, the present disclosure relates to sensor-based vision systems.
Displays are utilized in a wide variety of applications including but not limited to medical, military, avionic, transportation, entertainment and computing applications. The displays can provide sensed images of an environment. In certain applications, enhanced vision images and/or remotely sensed images are generally provided to the display to augment an operator's view of an environment or target. The enhanced vision image or remotely sensed image are generally provided by sensors (e.g., cameras) directed toward the environment or target.
In one exemplary application, displays are used in head down display (HDD) systems, head up display (HUD) systems and wearable displays, such as, helmet mounted display (HMD) systems. In vehicle (e.g., aircraft) applications, HUD and HMD systems advantageously allow operators (e.g., the flight crew) to maintain eye contact with the outside environment while simultaneously viewing display information from vehicle systems and sensors in a graphical and alphanumeric format overlaying the outside world view. The display information can include an enhanced vision image or remotely sensed image from a camera or other imaging sensor (such as a visible light imaging sensor, night vision equipment, infrared imaging sensor, millimeter wave radar imager, a remote camera, etc.).
In aircraft applications, enhanced vision systems (EVS) can be used for landing and can be designed to extract information about air field visible landing aids in low visibility conditions, such as, heavily scattering fog, and other conditions. Aircraft lights (e.g., anti-collision lights) can provide light that can back scatter when illuminating the fog and can therefore blind or adversely affect the operation of the EVS.
Aircraft lights can include one or more anti-collision lights. The anti-collision lights illuminate the vital areas around the airplane. The field of coverage generally extends in each direction within at least 75 degrees above and 75 degrees below the horizontal plane of the airplane. The arrangement of the anti-collision lights generally gives an effective flash frequency of not less than 40, and not more than 100 cycles per minute in certain applications. The effective flash frequency is the frequency at which the aircraft's complete anti-collision light system is observed from a distance, and applies to each sector of light including any overlaps that exist when the system consists of more than one light. Each anticollision light's effective intensity generally must equal or exceed 400 candles at an angle of 0 to 5 degrees above or below the horizontal plane of the aircraft. Wing tip mounted anticollision lights can provide significant back scatter due to their high power.
Lights associated with other types of vehicles can also cause back scatter which interferes with images captured by sensors (e.g., cameras). Ships, boats and other vehicles can have similar lighting systems that can affect display systems
Accordingly, there is a need for a system for and method of providing an optimal enhanced vision or remotely sensed image. There is also a need for systems for and methods of reducing light back scatter effects associated with a sensed image. There is a further need for systems for and methods of displaying enhanced vision images during approach and/or landing without back scatter or blinding affects. There is still a further need for systems for and methods of providing sensed vision image coordinated or synchronized with sources of light.